冲击位置对斜搭接接头冲击后拉伸性能的影响

低速冲击损伤对复合材料胶接结构的力学性能存在威胁。对在搭接区域3个不同位置承受低速冲击的斜搭接接头进行冲击后拉伸试验，并分别建立胶接接头冲击及冲击后拉伸有限元模型。试验结果表明：冲击位置在搭接区尖端背侧，造成的凹坑深度最大，冲击后拉伸强度最低；冲击位置在搭接区中部，凹坑深度最小，冲击后拉伸强度最大；冲击位置在搭接区尖端侧，凹坑深度及冲击后拉伸强度居中。有限元分析结果表明胶层损伤和复合材料纤维损伤的大范围扩展是导致结构失效的主要原因。

Tensile behavior of scarf joints after impact in different locations

The damage introduced by low-velocity impact is a threat to composite bonded joints. Scarf joints were impacted in three different locations of joint areas and then tensile test after impact was conducted. Finite element models of impact and tensile after impact of scarf joints were established respectively. The test results demonstrate that when impact occurs at the back face of tips, the indentation depth is the largest and the tensile strength after impact is the lowest. When impact occurs at the middle of joint area, the indentation depth is the smallest and the tensile strength after impact is the highest. When impact occurs at the front face of tips, the indentation depth and tensile strength are medium. The finite element analysis results show that the major cause of structural failure is the extensive expansion of adhesive damage and fiber cracks.